Record levels of stockpiling goods was not enough to mask the decline, but researchers at the accountancy firm said the activity may mean prospects for manufacturers are even worse than the numbers suggest, presenting a “real risk” of economic contraction in the first three months of 2019.

Peter Hemington, a partner at BDO, said: “Manufacturing firms have been ramping up their preparations for a disorderly Brexit, in large part through the stockpiling of imported goods. This has had the effect of inflating activity levels. So the underlying slowdown is probably rather worse than suggested by our headline figures. Stripping out the impact of these Brexit preparations, there is a real risk that the economy will contract in the first quarter.”

In the month that Prime Minister Theresa May’s hard-fought, business-backed Brexit deal was crushed by MPs, British businesses also suffered a significant knock in confidence. BDO’s so-called optimism index scored 99.98, the first time it has dropped below 100 since December 2016.